Coder == Carpenter
Degree == Architect
Being able to write code is a skill. You can put together some good stuff, but you wouldn't want them designing a skyscraper.
Now a carpenter who has lots of experience definitely picks up many tricks of the trade and will understand things better. But can they do the math to understand how wind shear should be accounted for, how many elevators are needed for the occupancy, or all of the fire codes? Is that to say an architect can build a beautiful piece of furniture? Not necessarily but a skilled carpenter certainly will.
Now someone with a CS or CE degree will be able to write code, not only from their first year basic course, but having to implement basic algorithms and data structures. Later, they'll get into Design Patterns to understand useful structures. They'll get into OS courses to understand inter-process communications and race conditions. And finally and potentially most importantly, they'll eventually learn how to evaluate their algorithms to ensure they're doing things in the most efficient manner.
Depending on what types of apps you're writing, simply knowing coding can be plenty. But at some scale and/or level of complexity, 4 years of college coupled with an internship/co-op of actual experience will outweigh just coding. Yes, experience will certainly get you there as will lots of personal motivation and curiosity. Don't get me wrong, there are plenty of kick ass carpenters but sometimes you need something more.